Native Plants
Falling Oaks
Dorothy C. Bliss
This past week a large southern red oak, three and a half feet in diameter fell across Woodland Avenue at the junction with Sumpter Street, just a block from my home. This huge monarch had snapped off at ground level. There were few roots visible, instead there was a gaping hole with evidence of fungal growth on the matted dead roots. Although inconvenienced since I had to walk home from this point, I was more intrigued since another of these apparently healthy oaks just across the street had crashed last fall, again, with few living roots. There was no splintering of the trunk, no strong winds involved but the massive oak had just toppled over. Why? This set me on a trail to try to find a reasonable explanation.
In talking with Don Davis, our city extension agent, I learned that a half dozen large oaks in Miller Park in the City of Lynchburg had met their demise in a similar manner. The Internet was helpful in providing some current facts on diseases of oaks and other hardwoods. Even more enlightening was the information presented in Charles E. Little's book, "The Dying of the Trees", a book I have brought to your attention recently. (See "Our Dying Forests" in the January, 2001 Newsletter.)
The pathogen or fungal causative agent of these root and butt rot diseases of hardwoods is caused by a basic diomycete which is probably a species of Armillaria, perhaps A. calvescens. This fungus may be spread by direct contact of the fungal threads (Mycelia) in the soil or by growth of fungal strands through the soil to uninfected trees or by spores. The most apparent observable signs of distress is the dieback of twigs and branches in hardwoods.
There is a large oak just outside the Randolph-Macon Woman's College Botanic Garden which has an excessive amount of dead and dying branches that continually litter the lawn and the edge of the garden. Thirty or more years ago, an oak had died in this spot. I was told that the disease of this oak was spread by root contact and within a few years several other oaks had died in a similar manner. I never saw the roots of the previous tree but suspect that it probably showed evidence of root decay and fungal growth. How long will the present oak remain standing before it, too, succumbs to root rot?
Although the fungus is the primary cause of the decay of the usually swollen butt, other agents may be involved. An urban setting is not an ideal environment for the growth of an oak which is usually a component of a forest. Acid rain, smog and other types of pollution may affect the vigor and health of the tree. In a city, lawns are frequently limed since grass grows best under alkaline conditions while oaks prefer deep fertile soils on the acidic side. In addition, compaction of soils and pollutants from rain water contaminated with street drainage may be of significance. How many more oaks that add so much to the beauty of our city lawns and streets will be lost in the coming years?
Charles Little describes how the oak trees and other hardwoods in the mixed mesophytic forest of the eastern United States are weakened by pollution and how ozone and the altering of the carbon/nitrogen ratio and the resulting root growth is impaired. The fungi grow rapidly in the weakened tissue. This results in the decay and rotting of the roots and the eventual toppling of the tree.
The death of the oaks is not an isolated incident but major forest trees are dying at an unprecedented rate, from the California coast to the sugar maples in New England to the eastern mesophytic forest. In a few words, our forests are dying.
The disastrous changes taking place in our forests is clearly described in Mr. Little's book which is available in most libraries and may be purchased in many bookstores.
Blackhaw Viburnum
Bob Eubank
If you want a plant to help attract birds and butterflies in mid-spring, Viburnum prunifolium (Blackhaw virburnum) is an ideal choice. Its spectacular blooms reach their peak during May. Although this large native shrub begins blooming in late April, it becomes very noticeable in May when its horizontal branches are covered with large flattopped creamy white cymes.
The rigid horizontal branches and thorn-like twigs resemble hawthorn, which is why the common name Blackhaw was given to this viburnum. The leaves are glossy green in the spring and resemble those of wild cherry, thus the assigning of the name prunifolium (leaves of Prunus) to this plant.
Blackhaw viburnum is native from Connecticut to Florida and west to Michigan and Texas. Bark from the roots was used by North American Indians to heal stomach, intestinal track, mouth and throat ailments. The Indians made decoctions to alleviate chills and fever and to relieve heart palpitations. Blackhaw berries also seemed to be the choice medicine for ulcers. Thomas Jefferson used this plant at Monticello two centuries ago, and it is among the natives grown there today.
Although Blackhaw is still very common and one of the most beautiful shrubs along the East Coast, I receive many calls each year to identify a strange, never-before-seen shrub or small tree that turns out to be Blackhaw viburnum. This shrub
has no major disease or insect problems, is mildew resistant and can be used not only in hedgerows but is so exceptionally ornamental that it can stand alone. Blackhaw will grow well in many types of soil from dry to damp, poor to rich, in sun or shade. Dr. Ruskin Freer planted Blackhaw at the edge of his lake property more than a half century ago, and it is still performing today as are specimens planted in much drier woodland soils on higher ground.
The beautiful flowers are a nectar source for butterflies and hummingbirds, and the bluish-black fruit in September is eaten by numerous species of birds and mammals, including man. I tried eating the fruit many years ago at the suggestion of Dr. Freer and continue to enjoy doing so every chance I get.
Blackhaw viburnum transplants easily and can be propagated from softwood cuttings, root cuttings and layering.
Swamp Rose
Bob Eubank
Rosa palustris, also known as swamp rose, is one of our native wild roses that not only provides beauty in the landscape but also serves as a source of food for birds.
It blooms for more than six weeks, beginning about mid-spring, with beautiful, fragrant magenta blooms and also provides one of the prettiest winter scenes in nature and in gardens with its purplish red bark and abundant scarlet rosehips. The rosehips, which measure 1/2 inch in diameter, provide important winter food for birds beginning about mid-winter but especially in late winter when food is scarce. Bird species such as cardinal, mockingbird, robin, thrush, bluebird, bobwhite, towhee, white throat, and many others eat the delicious vitamin-rich rosehips.
Rosa palustris is a tough and disease-resistant plant that, unlike pampered hybrid roses, does not require chemical controls that endanger birds, bees, and butterflies. It is called swamp rose because it grows naturally in wet or damp spots such as floodplains, margins of swamps, and along streams and springs in eastern North America and into Canada. It cultivates easily and though it doesn't like extremely dry conditions, it does not need to be grown in a swamp. Yards and gardens with poor drainage areas are also ideal for this plant. Try using it around birdbaths or water features to create a natural scene.
The canes usually grow to around six feet tall, but some of my plants have grown to approximately eight feet, with arching canes, which give the plant a nice shape. When massed, the effect of Rosa palustris is breathtaking, not only when it is in flower, but also in winter with its striking bark and rosehips.
Rosa palustris can be propagated easily from stratified seed, softwood and hardwood cuttings, layering, and root division. My collection came from successful cuttings and layering, although Rosa palustris and close relative Rosa virginiana (another great native shrub) are also available at various native plant nurseries.
Toler's Coralroot Orchid
Stan Bentley
In mid-April of 1995, a group of college students and their teacher, Rich Crites, were on a biological study outing in the Jennings Creek area of Botetourt County, Virginia. The group came upon a large population of Wister's coralroot orchid (Corallorhiza wisteriana). The general group of orchids known as coralroots (Corallorhiza) is a genus of plants that have no leaves. The lack of leaves, of course, means no chlorophyll is present to convert into food. All orchids are dependent upon some type of mycorrhizal fungus for at least part of their nourishment. With no leaves, coralroot species are particularly dependent upon their fungus and the relationship of that fungus with other plants. This unusual arrangement alone makes coralroots interesting plants to study.
Coralroots ordinarily have very beautiful but tiny flowers. So when one comes in contact with these plants, there is a rare treat in store for the observant nature lover. Prior to 1995, all of the then known species of coralroots in North America except Wister's coralroot (Corallorhiza wisteriana) were known to have a particular color form variation. This color form occurs rarely and is often referred to as an "albino form." These forms are not really albinos in the strict sense but rather are a pale yellow in color and lack the gorgeous purplish-red spots and markings seen in most flowers of coralroot plants.
On that fateful day along Jennings Creek, some of the students noticed that a few of the Wister's coralroot plants were yellow. Rich Crites knew that the plants were special, just how special became the question of the day. Crites had the foresight to contact his friend Bobby Toler and tell him about the plants. Bobby then contacted me. Bobby and I were soon on our way to Jennings Creek. I was really excited to see these plants that I had never before seen. But, I too, was not aware just how special the plants were. There were only four yellow plants. Although they had been stepped on, likely by trout fishermen, the plants were still in good enough condition for pictures.
I began to research these yellow colored Wister's coralroots as soon as I got home. After several days, I began to realize that these particular plants had likely never been scientifically described or named. I called Bobby and he agreed to go with me to take a specimen that would serve as a voucher to be placed in the herbarium at Virginia Tech. During the course of research for my book Native Orchids of the Southern Appalachian Mountains, I still never ran across a reference to a yellow form of Wister's coralroot orchid. I then decided to formally describe this new form in our book. Scientifically, the yellow forms of other coralroot species have generally been referred to as forma flauida - meaning yellow. To separate this new yellow form of Wister's coralroot further from yellow forms other species I decided a new variation could be applied in naming the form. In recent years, new scientific names for plant species have often been taken from the name of the discoverer or another prominent botanist - usually one associated with the area of botany from which the new plant comes. Recent new orchid names have somewhat followed this trend i.e. Keenan's fringed orchid (Platanthera xkeenanii) a new hybrid was named in 1993 for the late Phil Keenan of New Hampshire; Jones' twayblade (Lipa xjonesii) another new hybrid discover by the author in 1992 and named for the late Bus Jones of Tennessee a founder of the now defunct "American Association of Field Botanists"; and Bentley's coralroot (Corallorhi bentleyi) a new species discovered by the author and later named for the author by Dr. John Freudenstein of Ohio State University in 1999. With this research in mind, I formally named the yellow form of Wister's coralroot Toler's coralroot (Corallorhiza wisteriana forma toleri) in my book, Native Orchids of the Southern Appalachian Mountains, University of North Carolina Press, Chapel Hill, 2000.
Unfortunately, in the six flower seasons since the discovery of Toler's coralroot, these yellow plants have not reappeared. But someday they will and this fact alone makes Toler's coralroot a very rare plant indeed. Watch for it I do - every year.
Golden Wood Poppy
During April and May your eye may be caught by the brilliant golden-yellow blooms of the wood poppy. Stylophorum diphy!lum.
This herbaceous plant grows 12 - 18" tall and has one to four incised basal leaves. Blooms are one and a half to two inches wide, four petaled, and appear at the top of the stem from a stalk which originates near the base of the stem leaves. There are numerous stamens with very slender filaments and narrow anthers. There is one pistil with a two to four-lobed stigma. The calyx has two slightly hairy sepals which soon drop from the plant.
Seed pods mature to a rough, hairy, dry ovoid containing multiple seeds which are conspicuously crested. While not a true rhizome, the underground stem is thickened enough to be considered rhizomatous. The plant has the saffron-yellow juice typical of
many members of the Papaveraceae or poppy family.
This native, also known as Celandine poppy, is much more attractive than its similar European cousin, Chelidonium majus, known simply as Celandine. It makes an attractive addition to shady borders and the wild garden. It needs rich, neutral or slightly acid soil.
Attempts have been made to use this plant for the same medicinal purposes as C. majus. There has been some success in treatment of jaundice, ringworm and corns using compounds derived from the plant's juices.
The Atlas of the Virginia Flora indicates C. majus has been found in 34 counties. S. diphy!lum, on the other hand, has been found in only six counties, all in the southwestern portion of the state. It is often found along the edges of forests or in very light; open woods. If it's blooming nearby, it will definitely catch your eye.
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